AGING EFFECTS ON A NEW POLYMERIC TRACK DETECTOR SR-90 AND A MODEL OF THE NUCLEAR TRACK FORMATION

The relationship between the detection sensitivity for charged particl es and the molecular structure of polymers like CR-39 was studied whil e changing the average chain length of the carbonate linkages cross-li nking the polyallyl chains. It has been found that the polymer shows t he highest sensitivity when the length of the carbonate linkages is ab out 1.6 times longer than that of CR-39. Just after polymerization thi s polymeric track detector named SR-90 has about 3 times higher sensit ivity than CR-39 but ageing effects on its sensitivity are very strong . In this connection a model of the latent track formation and the mec hanism of the track fading are discussed on the basis of the recombina tion of free radicals produced by charged particles.